1. Technical Field
The present invention relates to a multilayer ceramic electronic component and a method for manufacturing the same, and more particularly, to a multilayer ceramic electronic component in which a portion of an internal electrode pattern in a section in which vertically neighboring internal electrode layers are not overlapped with each other has a thickness thicker than those of the other portion of the internal electrode pattern, and a method for manufacturing the same.
2. Description of the Related Art
In a multilayer ceramic condenser (MLCC), which is a multilayer ceramic electronic component, a technology of increasing capacitance capable of being implemented per unit volume to thereby reduce a size of the multilayer ceramic condenser and increase a capacitance thereof has been developed.
The MLCC is manufactured as follows. A slurry in which dielectric powders and additives are mixed is formed on a film to thereby manufacture a uniform dielectric sheet. An internal electrode is printed on the dielectric sheet according to a desired pattern to thereby manufacture a printing sheet. The printing sheet is cut to have a predetermined size and is then stacked to thereby form a stack bar. Next, the stack bar is compressed and then cut according to individual chip sizes. A cut green chip is subjected to baking-out and firing to thereby become a fired chip. Next, an external electrode is formed and plating and packaging is then performed to thereby complete the MLCC.
The MLCC, which is the multilayer ceramic electronic component according to the related art, will be described with reference to FIG. 7 showing a cross section of a multilayer body of the multilayer ceramic electronic component according to the related art.
The MLCC is manufactured by stacking several layers of printing sheets in which pastes for an internal electrode 30 are printed on ceramic dielectric sheets 10 and firing them as shown in FIG. 7. The stacked internal electrode layers 10 need to alternately contact external electrodes (not shown) formed on both sides of the MLCC so that they have different polarities. Therefore, spaces in which the electrodes are not printed, that is, steps or step gaps G are formed in a marginal portion M in an L direction (a length direction), as shown in FIG. 7. These steps G are partially alleviated in subsequent stacking and compressing processes. However, ultimately, they have lower density as compared to an overlapped section and become a main cause of crack generation due to stress in a subsequent process.
Particularly, in accordance with the trend toward the MLCC having a small size and a high capacitance, the stacked number has increased. Therefore, owing to an increase in accumulated stepped height difference in the marginal portion M shown in FIG. 7, in the subsequent process, a crack is easily generated due to the increased stress.
In order to solve this problem, a method for depressing the marginal portion M by enhancing compression at the time of compression of the marginal portion M in order to alleviate the accumulated stepped height difference in the marginal portion M has been used.
Meanwhile, a method for printing dielectric pastes in the marginal portion at a thickness that is the same as or lower than a thickness of the printed internal electrode layer in order to overcome the step in the marginal portion has been suggested in Korean Patent Laid-Open Publication No. 2002-0009451.
In the case of the method for depressing the marginal portion M by enhancing compression of the methods suggested in order to alleviate the accumulated stepped height difference in the marginal portion as described above, when compression excessively increases, a cutting defect due to deformation of a bar may increase. Further, in the method for depressing the marginal portion M by enhancing compression, the electrode and the dielectric in the overlapped portion are deformed and/or extended, such that electrical characteristics such as IR or BDV and reliability are deteriorated. As a result, a scheme of overcoming the accumulated stepped height difference through the enhancement of the compression has a limitation.
Meanwhile, the method suggested in the Korean Patent Laid-Open Publication No. 2002-0009451 may be effective in overcoming the step to thereby suppress the crack generation. However, separate dielectric pastes having a viscosity appropriate for printing and having solid contents appropriate for controlling a contraction percentage are required, and design of a pattern for dielectric printing becomes complicated for precise printing.
Therefore, a basic solution for the problem due to the accumulated stepped height difference in the marginal portion has been demanded.